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Patented Oct. 28, 1890.

0 S A N W m m HB m R L A W U A m U 9 m M m a m N UNITED STATES PATENT OFFICE.

ARTHUR O. W'ALWORTH, OF NEN TON, MASSACHUSETTS, AND CARLETON W.

NASON, OF NEWV YORK, N. Y.

STEAM-BOILER.

SPECIFICATION formingpart of Letters Patent No. 439,261, dated October 28, 1890.

Application filed November 22,1889. Serial No. 331,213. (No model.)

To all whom it may concern:

Be it known that we, ARTHUR O. WALWORTH and OARLETON WV. NAsON, citizens of the United States, residing, respectively, at New- 5 ton, Middlesex county, State of Massachusetts, and in the city, county, and State of New York,

have invented certain new and useful Improvements in Steam-Boilers, fully described and represented in the following specification x and the accompanying drawings, forming a part of the same.

This invention relates to that class of boilers known as drop-tube boilers, in which the water-tubes depend from the steam-drum i and are closed at their lower ends, it being the object of the invention to providea boiler of this class which shall be more perfect in its construction and economical in its operation than those heretofore in use.

To that end the invention consists in various details in construction and combinations of parts, which can only be fully understood by an illustration and a detailed description of a boiler embodying said improvements. All 2 5 further preliminary description will therefore be omitted and a detailed description of the improvements given, reference being had to the accompanying drawings, in which- Figure 1 is a front elevation of a boiler of the class referred to, embodying the present invention. Fig. 2 is a vertical sectional ele- Vation of the same. Fig. 3 is a horizontal section taken on the line 3 of Fig. 2. Fig. 4 is a sectional detail taken on the line 4; of Fig. 3.

Referring to said drawings, it is to be understood that as to its general construction and organization the boiler is substantially the same as those heretofore in use and constituting the general class of drop-tube boilers.

4o Located at the top. of the boiler is the steam chamber or drum A, the bottom of which is perforated to receive the ends of the vertical tubes B, which are suspended from the bottom of the drum. The tubes B are arranged in concentric rows, the outer row of tubes being of larger diameter than the others, and the tubes decrease in length from the outer to the inner row, so as to form a dome-shaped space at the bottom of the boiler, which con- 5o stitutes the fire-box or furnace. The tubes 13 are closed at their lower ends and open at their upper ends, as is common in this class of boilers, the tubes being provided with the usual longitudinal diaphragms to insure circulation. Passing upward through the center of the steam-drum, and communicating at its lower end with the furnace portion of the boiler inside the inner IuW of tubes, is a flue C, which communicates at the top of the boiler with the chimney D. Passing downward through the flue O is a threaded rod E, which carries at its lower end a horizontal baffleplate F, which is located within and substantially fills the space inside the inner row of tubes. This baffle-plate operates to deflect the flame and hot gases arising from the fuel in the furnace laterally, and cause them to pass between and circulate among the depending tubes instead of passing directly upward into the flue O. This plate is adjust- 7o able by means of the threaded rod E, so that it can be located at diflerent distances from the lower end of the flue, and thus vary the point at which the flame and hot gases from the furnace are deflected among the tubes as the different working conditions of the boiler may require. 7

The furnace is provided upon one side with the usual door G for the introduction of fuel, andthis door is surrounded byawater-circulating passage H, which communicates with the steam-drum and is kept supplied with water by means of one or more of the outer row of tubes B, with which it communicates, as best shown in Fig. 3. The boiler is provided with the usual grate I, beneath which is a space K, forming the ashpit.

In order to protect from the extreme heat of the furnace the lower ends of the outer row of tubes, which extend downward to a point on a level with the grate, they are protected by suitably-formed pieces of fire brick L, which fit in between the tubes and are provided upon their inner faces with flanges Z, which project so as to partiallybut not wholly 5 cover the inner sides of the tubes and protect them from the heat of the furnace. For the purpose of maintaining these brick in position, the bottom of the furnace is provided with an annular flange m, (see Fig. 4,) which I00 fits into recesses in the lower ends of the brick, while the upper ends of the brick are provided with recesses n, (see also Fig. 4,) into which project the lower ends of the next row of tubes, thus preventing the brick from moving inward from their proper position. In order to remove any one or-more of the brick,

it is only necessary to raise it until it is clear' of the flange m, and then move its lower end inward until it is free from the tube which ered by bands 0,-Which are provided with bolts 0, by which they are clamped together around the sections of the casing so as to hold them in place. By loosening the bolts 0 the bands can he slipped up or down, and thus permit the removal of any one or more of the sections N, to gain access to the asbestus or to the interior of the boiler, if desired.

The boiler, as herein shown, is provided with an ordinary diaphragm-regulator P, the lever of which is connected to the draft-door Q of the ashpit, and also with a draft-doorR, located in the side of the chimney D. The

operation of this regulator is the same as usual. When the pressure in the boiler falls back to the normal point, the regulator will operate its lever to close the door R and open'the door Q, thus admitting a draft to the furnace.

That we claim is 1. The combination, in a drop-tube boiler, of the vertical water-tubes decreasing in length from the circumference toward the center of the boiler, and the blocks of firebrick arranged around the circumference of the fire-box to protect the lower ends of the longest tubes, substantially as described.

2. The combination, in a drop-tube boiler, of the vertical water-tubes surrounding the fire-box, and the blocks of fire-brick arranged to fit in between the tubes-and having flanges Z to overlap and partially cover and protect the tubes, and also arranged to fit in behind and be held in place by the shorter tubes, substantially as described.

In testimony whereof we have hereunto set our hands in the presence 01' two subscribing witnesses.

ARTHUR O. W'ALWORTH. OARLETON W. NASON.

lVitnesses as to signature of Arthur 0. \Valworth:

APPLETON W. SMITH, CHAS. F. FLETT.

Witnesses as to signature of Carleton XV. Nason:

SAMUEL A. N ASON, CHAS. E. CoRYELL. 

